The power generation system of an automobile may include a battery, a generator and a voltage regulating device. The battery can provide power for starting the engine, the power required by the engine after ignition can be supplied by the generator, and the generator can charge the battery. As the power generated by the generator (e.g., alternator) is an alternating current (AC), and the power stored in the battery is a direct current (DC), a rectifier diode may be provided on the generator in order to convert AC into DC. One of the functions of the voltage regulating device is to block current that is not within the specification and sense operational instructions of the generator.
In order to increase the fuel efficiency, synchronous rectification method may be used, and Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFET) are used instead of the diode, and are switched with the cooperation of a two-terminal voltage comparison detection. However, in the vehicle environment, there are usually a lot of noises, and the MOSFET components susceptible to false switched-off or false switched-on due to the noise. As a result, a reverse current or a large current is generated, and power is wasted. In order to solve these problems, a filter or hysteresis comparator may be added to avoid noise interference. However, a powerful filter or hysteresis comparator may cause even greater power loss.
Therefore, there is a need for a method and a system for controlling a rectifier that solve the aforementioned problems.